Cell surface glycocalyx protects against histone-induced cell death. (A) CHO-K1 and CHO-A745 cells were incubated with or without histones (50 µg/mL for 4 hours at 37°C), and membrane permeability to PI was measured by fluorimetry. (B) EA.hy926 cells grown in the presence or absence of 4-MU (100 µM for 24 hours at 37°C) were incubated with or without histones (50 µg/mL), and membrane permeability to PI was measured by fluorimetry. Data are presented as mean ± SEM of 3 independent experiments using one-way ANOVA with Bonferroni’s multicomparison test. ****P < .0001, ***P < .001.